These posts will be updated frequently, feel free to let me know if I forgot anything or if you disagree with something.
This is meant as a comprehensive compilation of all the Diablo lore, also pointing out inaccuracies and contradictions.

The first step is establishing a chronology and find all the source which give information on each event.

The Dawn [1]

The Great/Eternal Conflict [1],[2],[9]

The Sin War [1],[2],[9]

The Mage Clan Wars [1],[9]

The Dark Exile [1],[2]

The Binding of the Three [1],[2],[3]

From the capture of Diablo up to his Awakening [1],[2]

From the Awakening of Diablo up to its defeat [1],[2]

From the Dark Wanderer up to the Shattering of the Worldstone [1],[3],[4]

From the Explosion of Mount Arreat up to when a Meteor Falls on the Tristram Cathedral [7],[8]

From when a Meteor Falls on the Tristram Cathedral up to the end of Diablo III [5],[6]

Book of Cain

Diablo I Game/Manual

Diablo II Game/Manual

Diablo II: LoD Game/Manual

Diablo III Beta

Diablo III Game/Manual

The Order

Sword of Justice

The Sin War Trilogy

Other Sources

Then let's list all the books in chronological order.

The Book of Cain
Covers most of the history of Sanctuary from the creation of the universe to recent times.

The Sin War Trilogy (Birthright/Scales of the Serpent/The Veiled Prophet)
Occurs 3000 years before the darkening of Tristram. Follows the story of Uldyssian.

Demonsbane
Occurs during year 302. Mentions of Arkaine and Horazon are made.

The Black Road
Spans over a year. Begins after the war between Tristram and Westmarch and ends after Tristram has been destroyed.

Legacy of Blood
Occurs in the weeks before the Dark Wanderer reaches Lut Gholein.

The Kingdom of Shadow
Spans over a couple of weeks. No precise hints are made about when the story occurs. Still we can assume, from Diablo's brief appearance at the end of the book, that a that time Diablo was back in the Burning Hells. So the story takes place after Mephisto has been defeated and while Diablo is in his sanctum.

Moon of the Spider
Takes place shorty after the destruction of the Worldstone. The story is a sequel to The Kingdom of Shadow.

The Order
Cover most of the 20 years between Diablo II and Diablo III.

It might also be useful to list all the major realms

Pandemonium

Pandemonium Fortress

Worldstone (Eye of Anu)

High Heavens

Chamber of the Council

Crystal Arch (Anu's spine, place angels spawn from)

Diamond Gates

Silver City

Burning Hells

Black Abyss

Hellforge

Tathamet's husk (place demons spawn from)

Sanctuary

The Afterdeath

The Void

The Beyond(1)

Trag'Oul's Realm

The Pearl(2)

Realm in which Anu rests(3)

All the other worlds which the likes of Trag'Oul are sentinel over.

(1) Realm Trag'Oul reveals to Uldyssian to unleash his power into, it's never explicitly named.
(2) The Pearl no longer exists, it was the place where Anu and Tathamet engaged in battle.
(3) Is said to be beyond this universe, could be considered to be another reality. Nothing else is known of the paradise Anu passed into.

A list of all the major characters (this list will probably get incredibly long and may have its own post/thread in the future)

High Heavens

Angiris Council

Auriel

Imperius

Itherael

Malthael

Tyrael

Others

Hadriel

Inarius (once advisor to the Angiris Council)

Izual

Burning Hells

Prime Evils

Baal

Diablo

Mephisto

Lesser Evils

Andariel

Azmodan

Belial

Duriel

Others

Astrogha

Lilith

Lucion

Sanctuary

Nephalem

Bul-Kathos

Esu

Helgrotha

Rathma (Linarian)

Vasily

Mage Clan (The Horadrim and the Yshari are not included as they are temporary orders/organizations)

Ammuit (illusion magic)

Ennead (alchemy, enchantments, alteration, transmutation)

Harakas

Sarandesh

Taan (Skatsimi rites)

Vizjerei (demonic conjuration and summoning, then later elemental magic)

Zann Esu (elemental magic)

Horadrim

Deckard Cain (1)

Jered Cain

Nor Tiraj (Vizjerei mage)

Tal Rasha

Zoltun Kulle (Vizjerei or Ennead mage)

Vizjerei

Bartuc

Horazon

Vischar Orous

Others

Abd al-Hazir

Adria

Archbishop Lazarus

Lam Esen

Leah

Kalan (Mendeln ul-Diomed)

King Leoric

Prince Aiden

Prince Albrecht

Uldyssian ul-Diomed

Others

Anu

Tathamet

Trag'Oul

(1) Not actually a Horadrim as the order dissolved some time after the Prime Evils were captured and before he was even born, but the last descendant of the order.

Here is a list of all the lore source, along with the degree of authority that should be given to each one.

Diablo III Game/Manual [Ultimate Authority]

Book of Cain [Sourcebook. High authority]

The Sin War Trilogy (Birthright, Scales of the Serpent, The Veiled Prophet) [Novels. High authority]

Begins: At the beginning of everythingEnds: With the creation of the universe

Before the birth of the universe there was nothing, save a perfect pearl.

In that pearl was Anu, a being made of shining diamond that was the sum of all thing.

Anu sought a state of total purity and in order to attain it casted all the evil aspects from himself.

The evil aspect formed together and out of them Tathamet, the Dragon, was created.

Anu and the Dragon engaged in battle against each other for uncounted ages, neither ever gaining the upper hand.

After countless millenia, they each delivered their final blows unleashing an explosion of light and matter that birthed the universe.

In the center of the universe lies the Eye of Anu, the Worldstone. It is the foundation stone of all places and times, a nexus of realities and vast, untold possibility.

From the remains of Anu and the Dragon, the High Heaven and the Burning Hells were formed.

Book of Cain p.9-12

The Great/Eternal Conflict​

Begins: Shortly after the creation of the universe. [1],[2],[3]Ends: Still in effect. [2],[3]

The Eternal Conflict is the unceasing war between the High Heavens and the Burning Hells. It was most commonly fought within the realm of Pandemonium where angels and demons battled over the control of the Heart of Creation, the Worldstone.

The Pandemonium Fortress is built around the Worldstone. [15]

Control of the fortress changed hands many time, allowing it to take on traits from both the High Heavens and the Burning Hells. [16]

Over time some angels and demons grew disillusioned with the Eternal Conflict and seized the Worldstone. The events resulting from this are listed bellow. After the vanishing of the Worldstone, the battle for possession of the Worldstone became the search for it.

~Year -100,000 to -50,000. Creation of Sanctuary. [14]

Inarius seizes the Worldstone and veils it from the sight of both the High Heavens and the Burning Hells. [4]

Inarius binds himself to the Worldstone. [5]

Inarius manipulates the Worldstone to create Sanctuary. [6],[7]

The nephalem are born out of the union of angels and demons. [8]

Inarius express his desire to erase the nephalem from existence, but due to the protests of the others agrees to consider their fate. [9]

Lilith murders every renegade angels and demons, leaving only Inarius and the nephalem. [10]

Inarius casts Lilith to The Void. [11]

Inarius alters the resonance of the Worldstone so that each succeeding generation of nephalem becomes less powerful than the previous until they no longer have any ability. [12]

Inarius instill a firm policy against the nephalem using their powers and bestows strict punishment upon those who use them. (He feared that their powers might draw the attention of the Heavens and the Hells and cause them to discover the existence of Sanctuary)[13]

There is no indications of when Izual made his assault on the Hellforge, but if we assume that it was Izual's intention to betray the High Heavens and that only a short amount of time passed between his capture and the planning of the exile of the Prime Evils, then we can narrow the timeframe to sometime after the Sin War trilogy (since the High Heavens weren't aware of Sanctuary's existence before it).

~Year -1700 to 900. The betrayal of Izual.

Izual attacks the Hellforge and is defeated.

Izual turns over the secrets of the Soulstones to the Prime Evils and helps them plan their exile to Sanctuary.

Izual spirit is bound within a terrible creature summoned from the Black Abyss, left to wander the Burnings Hells for eternity.

Azmodan and Belial make a pact with their minor brethren to overthrow the Prime Evils.

First Civil War. All of Hell goes to war against the Prime Evils.

Year 964. The Prime Evils are banished. A third of the Burning Hells' legions are annihilated in the process.

"There is a war that rages on even now, beyond the fields that we know - between the utopian kingdoms of the High Heavens and the chaotic pits of the Burning Hells. This war is known as the Great Conflict, and it has raged and burned longer than any of the stars in the sky."
- Diablo I Game, Lore Book, The Great Conflict

"Thus was how all of what we know beganâ€¦ In time, the Lords of Hell and the angels of Heaven met and clashed. The battle raged unceasing, and thus would come to be known as the Eternal Conflict."
- Book of Cain, p.12

"Long ago, and angel known as Inarius seized the Worldstone and, through some impossible act of magic, veiled it from the sight of both Heaven and Hell. He had accomplished this with the aid, I presume, of the mysterious demoness Lilith and a cadre of other angels and demons who had grown disillusioned with the Eternal Conflict."
- Book of Cain, p.16

"Somehow he was able to alter the Worldstoneâ€™s focus â€” perhaps with the unknowing help of his fellow renegades â€” then bind himself utterly to it and thus ensured that none who had assisted him in its theft would be as powerful."
- The Veiled Prophet, p.277

"Inarius succeeded in manipulating the power of the stone to create the world of Sanctuary, a hidden paradise where he and his followers could live free from the madness of unending strife."
- Book of Cain, p.16

"I forged this world from raw forces taken from the place of Creation! I sculpted the lands and filled the seas. All exists because of me; all remains at my whimâ€¦including you, my child."
- The Veiled Prophet, p.64-65

"Youâ€¦all humansâ€¦are the spawn of our coupling! From demon and angel came the nephalem, greater than anything ever created in the cosmos!"
- Birthright, p.413

"Inarius thought the nephalem a disease, a disgrace to what he was. To him, we should have never been. He only agreed to consider our fate as opposed to erasing us from existence because of the protests of the others."
- Scales of the Serpent, p.309

"Inariusâ€™s own lover, the demon Lilith, secretly stalked the other demons and angels, slaughtering them one by one. In her madness and ambition, she saw herself as the savior of the children and also, thus, the only one with the right to mold their destiny."
- The Veiled Prophet, p.12

"the angel had cast her out into the endless void, never to return."
- Birthright, p.488

"the Worldstone also began a steady and subtle dampening process. Each succeeding generation of nephalem became far less powerful than the previous, until, in very short order, those next born were bereft of any ability."
- Scales of the Serpent, p.309

"There are few of us remaining, for when only my father was left of the original refugees, he was strict in his punishment of those who used their powers."
- Scales of the Serpent, p.247

"In fact, this was home for him, as much as anywhere had been in a thousand lifetimes."
- Birthright, p.441

"Further research suggests that in time, an archangel called Tyrael ordered a bastion to be built around the Worldstone, a stronghold which would come to be known as the Pandemonium Fortress."
- Book of Cain, p.15

"In any case, over the course of the Eternal Conflict, the fortress changed hands between angels and demons. Thus, it has taken on structural and metaphysical traits from both the High Heavens and the Burning Hells."
- Book of Cain, p.16

The Sin War​

Begins: ~Year -2500 to -2000. The discovery of Sanctuary by the Prime Evils. (1)Ends: Still in effect.

Uldyssian contains within him all the devastation his power has caused. [31]

Uldyssian unleashes the fury that he kept imprisoned in the beyond, negating his very being in the process. [32],[33]

This final release of energy reseted the Worldstone to its original state, stripping the powers from the edyrem in the process. [48]

The Angiris Council votes on the fate of Sanctuary. Imperius votes for its destruction. Malthael abstains. Auriel, Itherael and Tyrael vote for its survival. [34],[35],[36],[37],[38]

A truce is made between the Angiris Council and the Mephisto. As long as it holds Sanctuary shall go untouched by either side. [39],[40]

Mephisto casts his mark on a point of Flux, preventing the burning hells from spreading their taint across Sanctuary. [41],[42]

In return, Inarius is turned over to Mephisto. [43]

Another pact, concerning the Worldstone, is made between the High Heavens and the Burning Hells. [44]

The memory of the events and of their powers are wiped from the edyrem. Only Mendeln, protected by Tragâ€™Oul, keeps his. [45],[46]

Mendeln takes the name of Kalan. [47]

(1) No official date is given for this event but we know that Malic has been granted more than two lifetimes[49]. Given that he was not the first high priest[50] we can guess the earliest date Sanctuary could have been discovered by the Burning Hells.

"The Cathedral of Light, though only of recent origin, seemed far stronger than most of its predecessors. Indeed, it and the longer-established Temple of the Triune seemed to be quickly becoming the two dominant forces seeking the souls of Kehjanâ€™s people."
- Birthright, p.6

"thisâ€¦more than three of your lifetimes agoâ€¦is where I found my way back to Sanctuary!"
- Scales of the Serpent, p.352

"The angel, distracted by the incursion of the Burning Hells into his world, did not notice her slow, subtle manipulation of the Worldstone. That manipulation had reversed his intentions, awakening the potential within the many humans now inhabiting Sanctuary."
- The Veiled Prophet, p.13

"The souls of most of my family are beyond the Prophetâ€™s gathering, brother! They died nearly ten years ago, all to plague!"
- Birthright, p.5

"Three thousand years before the darkening of Tristram, Uldyssian, son of Diomedes, was a simple farmer from the village of Seram."
- Birthright, back cover

"And, at last, the demon became as Uldyssian had saidâ€¦nothing."
- Birthright, p.506

"Uldyssian had caused the demon to cease to exist. According to Rathma, there was something different about such a fate"
- Scales of the Serpent, p.419

"Gulag was literally torn in two. The halves quivered like pudding. A moan escaped bothâ€”
Then, with one last rumbleâ€¦the demon melted."
- Scales of the Serpent, p.40

"Uldyssian himself had altered the Worldstone in its very makeup. Altered it in a manner that apparently even Inarius could not unmake."
- The Veiled Prophet, p.278

"The mountaintop exploded. The force unleashed by the angel ripped up snow, ice, and rock in great chunks."
- Scales of the Serpent, p.370

"The entire top of the peak had been radically altered. Now, it looked as if the mountain had grown a giant, three-fingered paw with jagged claws on two of the digits. He and Rathma stood on the outer edge of the third, a drop of well over a thousand feet merely one step away."
- Scales of the Serpent, p.372

"Astrogha had not merely fled to safety; he had fled the Triune entirely."
- Scales of the Serpent, p.384

"Yes. Tyrael. I believe that the Angel of Justice has come on his own to judge his brotherâ€™s crimesâ€¦and, in the process, Sanctuary."
- The Veiled Prophet, p.108

"With a shattering sound worthy of the colliding Shards of the Worldstone, the Kiss of Mephisto was no more."
- Scales of the Serpent, p.502

"But his own spell had already come to fruition. The entire roofâ€”and all three towers, Uldyssian knewâ€”collapsed. Hundreds of thousands of tons of stone and wood fell upon the chamber and all else. "
- Scales of the Serpent, p.515

"Lilith screamed and cursed, but her voiceâ€”as well as sheâ€”grew tinier and tinier. The sphere became a marble, then the size of a pea.
And then, for all mortal purposes, shrank so tiny as to become nothing."
- Scales of the Serpent, p.525

"Because Inarius has done â€” again â€” the unthinkable. He has made a pact with one of the Threeâ€¦made a willing pact."
- The Veiled Prophet, p.275

"They left Tragâ€™Oul with the understanding that all his years of aiding the Worldstone in shielding Sanctuary from the outside had come to naught.
It was not merely one angel who had discovered Inariusâ€™s creation. The High Heavens themselves now knew of the world."
- The Veiled Prophet, p.261

"Even now, he attempts to blind them to Sanctuaryâ€™s true location. And if that fails, he will try to bar their way with his power."
- The Veiled Prophet, p.331

"And so Diablo looked upon himself.
Under any other circumstances, Uldyssian doubted that the demon would have been affected. Prepared for such a trick, the Lord of Terror would have adjusted."
- The Veiled Prophet, p.297

"Diablo twisted and turned as his own insidious power wreaked havoc on him. He had only glanced for a moment, but the fears of the master of fear were evidently monstrous, indeed."
- The Veiled Prophet, p.297

"With that, he cast the sphere and Rathma into the void."
- The Veiled Prophet, p.349

"The strainâ€¦the strain of reaching out all the way here isâ€¦is growing worse. Mendeln ul-Diomed, you must act as the link between myselfâ€¦and Rathmaâ€¦if we are to save him."
- The Veiled Prophet, p.367

The shock of confronting her â€” especially since she was supposed to be dead â€” shook Mendeln so much that he nearly demanded that Tragâ€™Oul immediately return him to his world.
- The Veiled Prophet, p.371

"Sanctuary is noâ€¦no longer shielded from theirâ€¦sight! The Heavenly Host knows they were misled. Tragâ€™Oulâ€™s grief at his failure was so very evident. The winged warriors are closing in on our world."
- The Veiled Prophet, p.374

"I sawâ€¦I saw into what could only be what Rathma called the Burning Hells, Uldyssian! The passage in the grasslands leads out of our world and into wherever they must exist!"
- The Veiled Prophet, p.399

"For now the sky looked as if it were not real, as if it were instead a vast drawing on a gargantuan piece of parchment. More impossible, that parchment had a vast rip running across it, a literal tear in the sky."
- The Veiled Prophet, p.469

"Uldyssian had severed the renegadeâ€™s link. Inarius no longer could call upon the Worldstone."
- The Veiled Prophet, p.476

"Uldyssian eyed the combatants. Raising his hands again, this time with the palms open, he willed the angels and demons to be pushed back."
- The Veiled Prophet, p.494

"Bracing himself and taking a deep breath, Uldyssian began willing the wild forces to return."
- The Veiled Prophet, p.502

"Uldyssian then drew it together again and let it pour out into the beyond, where it spilled in all directions."
- The Veiled Prophet, p.507

"Then, finishing what had to be done, what he desired to be done, Uldyssian ul-Diomed let himself scatter throughout all, his passing from the mortal plane marked for those below by a fiery yet arresting flash of light that did not frighten but rather gladdened."
- The Veiled Prophet, p.507

"the renegade must be forever imprisoned and his nest of demon-spawn eradicated!"
- The Veiled Prophet, p.512-513

"Whatever the choice, in the end it does not matter for meâ€¦. I abstain."
- The Veiled Prophet, p.513

"Let their potential be developedâ€¦for in them I think there is a chance that we may see the end of our struggle at last!"
- The Veiled Prophet, p.513

"they also have the greatest potential to serve the lightâ€¦a potential that could surpass our own rolesâ€¦and so I vote that they be given their chance."
- The Veiled Prophet, p.514

"I did call them abominationsâ€¦and I was wrong! My vote is for themâ€¦for I would see what they might becomeâ€¦and marvel in it."
- The Veiled Prophet, p.517

"Sanctuary is much more than we envisioned! All you said is true, and we would let it grow and see where it leads, good or ill, untouched by either side."
- The Veiled Prophet, p.519

"Himâ€¦let he whose crimes are already legion among you now be cast to me to pay for my loss â€” and the sealing of the truce, as it happens."
- The Veiled Prophet, p.520

"what do any of you now suggest be done to prevent the burning hells from spreading their taint across this world"
- The Veiled Prophet, p.517

"There rests a point of flux! A point where this world was sealed togetherâ€¦your mark."
- The Veiled Prophet, p.521

"From out of the shadow burst a score of inky tendrils. They wrapped eagerly around the renegade angel. Without effort, they dragged him back into the darkness with them."
- The Veiled Prophet, p.522

"His voice seeping with satisfaction, Mephisto murmured, â€œAnd the cavern and the find within?â€
Imperius shifted as if angry. Tyrael replied, FOR WHAT SHALL BE NEEDED TO BE DONE THERE, ANOTHER PACT MUST BE MADE."
- The Veiled Prophet, p.522

"Back to the beginning, Tyrael reiterated. And from there, we shall leave them to their own destiny, whether good or ill, for as long as the truce holds."
- The Veiled Prophet, p.524

"I would call you Kalan. In the tongue of that of which I am, it means teacher, for you have risen far too high to be called by me a mere studentâ€¦and we have need of you to show others the truth of the Balance."
- The Veiled Prophet, p.529

"Is has been suggested in the Books of Kalan that Uldyssian's final release of energy flooded the Worldstone, resetting it, and thereby stripping his followers of their nephalem powers."
- Book of Cain, p.79

"Malicâ€”who himself had supposedly had not one, but more than two lifetimes granted him by the master"
- Scales of the Serpent, p.181

"He had risen from an eager acolyte to his venerable role through determination, creative thinking, and devotion to his master."
- Birthright, p.99

The Mage Clan Wars​

Begins: After the founding of the Triune. [1]Ends: ~Year 1004. The creation of the Horadrim Order. [2]

~Year -715. The Vizjerei encounter the umbaru tribes and try to take advantage of them to establish an army by using them as demon-possessed victims and transforming them in savage goat-like creatures. [3],[4],[5]
~Year -715 to -700. Some of the umbaru tribes go at war against the Vizjerei. [6]
~Year -700 to -500. The umbaru tribes become obsessed by their desire to defeat the Vizjerei. They succeed in capturing one of the mage and coerce him into transforming them into khazra. [7],[8]
~Year -500. The remaining umbaru tribes send their witch doctors to defeat Zagraal, the leader of the khazra, from which the khazra draw their power. [9]
~Year 270. Horazon and Bartuc raise to dominance from within the Vizjerei. [10]
~Year 275. Bartuc lays siege to Viz-jun and is defeated by a group of Vizjerei lead by his brother Horazon.
~Year 275. Horazon creates his Arcane Sanctuary.[11]
~Year 280. The Viz-Jaqâ€™taar, the secret Order of the Mage Slayers, otherwise known as the Assassins, whose sole purpose is to police the mage clans, destroying corruption wherever they find it, is founded by the surviving Vizjerei.

"The mage clans were more than happy to be rid of the powerful sect, which had been the first to wrest influence away from the spellcasters. Indeed, that had been in great part the cause of the first feuds, as clans had struggled to seize from one another what stature remained."
- The Veiled Prophet, p.4

"The order, known as the Horadrim, consisted of wizards from the diverse and numerous mage-clans of the East. Employing disparate magical practices and disciplines, this unlikely Brotherhood succeeded in capturing two of the Brothers"
- Diablo I Manual, Librarius Ex Horadrim - Book One, p.66

"This state of affairs changed dramatically when they encountered the Vizjerei about two thousand years ago (if my translations prove to be correct)."
- Writings of Abd al-Hazir, entry no.009

"A faction of the Vizjerei resolved to construct an army using demon-possessed victims, and the peaceful umbaru clans seemed to fit the Vizjerei's needs."
- Writings of Abd al-Hazir, entry no.009

"It is unknown how the clans first came into contact with the Vizjerei, but within the span of a decade or so, some of the future khazra clans had turned from their peaceful existence to all-out warfare with the Vizjerei."
- Writings of Abd al-Hazir, entry no.009

"As decades of savage warfare took their toll on the umbaru's culture and minds, the clans began to search for any means to prevail over their enemies."
- Writings of Abd al-Hazir, entry no.009

"at some point during the next two hundred years they decided to use the Vizjerei's strength against them. To this end, the clans actively sought to capture a mage to do their bidding. Eventually they succeeded in violently coercing one of their captives to help them not only gain control over their transformed clan mates, but to have themselves transformed as well in order to fully drive the Vizjerei out of the Teganze."
- Writings of Abd al-Hazir, entry no.009

"After years of this terror, their previous brothers, the umbaru of the lower Teganze, sent their sacred witch doctor warriors to eradicate the khazra's threat to the region. Filled with otherworldly power, the witch doctors cut a swath of destruction through the khazra until they confronted Zagraal himself. In a now-legendary battle, the valiant heroes fought to the last man before finally bringing Zagraal down."
- Writings of Abd al-Hazir, entry no.009

"In the third century, two brothers rose to dominance from within the ranks of the Vizjerei clan of mages; their names were Horazon and Bartuc."
- Diablo II: LoD Manual, The Assassins

"Nearly a thousand years ago, Horazon rose to the fore of the Vizjerei mage clan. Horazon used the knowledge of the Vizjerei to summon and control demons from Hell.
Though a powerful Summoner, Horazon feared that the Lords of Hell would punish him for enslaving their brethren. Thus, the Summoner created for himself an Arcane Sanctuary."
- Diablo II Game, Drognan, Arcane Sanctuary quest

The Dark Exile​

Begins: Year 964. The exile of the Prime Evils to Sanctuary. [1]Ends: Year 1019. The capture of Diablo inside a Soulstone. [1]

The Prime Evils, weakened and bodiless, are banished to Sanctuary.

The few demons who still pledge allegiance to the Prime Evils flee to Sanctuary to seek out their lost Masters.

Azmodan and Belial begin to argue over which of them holds the higher authority. They take up arms against each other, starting the second civil war.

For many months King Leoric secretly fights the evil presence that twists his thoughts and emotions.

Year 1259. Ogden purchases the Tavern of the Rising Sun.

Leoric becomes increasingly deranged and orders the immediate executions of any he finds guilty of plotting against the kingdom.

The people of Khanduras begin to call Leoric the Black King.

Lazarus convinces Leoric that the kingdom of Westmarch is plotting against him, secretly planning to dethrone him and annex Khanduras into its own lands.

Leoric declares war on the kingdom of Westmarch.

Lachdanan is appointed by Lazarus to lead the armies of Khanduras into Westmarch. Many of the high-priests and officials are forced on errands of diplomatic urgency.

Diablo is unable to completely possess Leoric. King Leoric is left maddened by Diablo's unsuccessful possession.

Year 1263. Lazarus kidnaps King Leoric's youngest son, Prince Albrecht. Many other children are taken that day, including Wirt who is dragged into the labyrinth by the small demons.

Prince Albrecht is possessed by Diablo.

Leoric accuses the townsfolk of kidnapping Albrecht and orders many of them to be executed.

Wirt's mother, Canace, dies from grief.

Griswold ventures in the cathedral and rescues Wirt, but only after the foul beasts had begun to torture him.

Defeated, Lachdanan orders the army of Khanduras to a retreat. They return to find the town of Tristram in shambles.

Leoric accuses Lachdanan of treason and orders he and his party to be executed.

Lachdanan orders his men to defend themselves. The battle ends after Lachdanan drive his blade through Leoric dark and corrupted heart.

With his dying breath, Leoric brings down a curse upon those who had betrayed him. That they would serve him even in death.

As his knights laid him to rest in his burial chamber, Diablo raised Leoric from the dead as the Skeleton King

All the knights are overcome by the curse of King Leoric. Only Lachdanan escapes the curse and heads down the cathedral to avoid putting Tristram in danger.

Lazarus, under the guise of searching for Prince Albrecht, lures a group of villagers into the cathedral and abandons them to a bloodthirsty butcher demon. Only a few, including Farnham and Griswold, escape with their lives.

Gillian is tormented by horrific nightmares that seem to be getting stronger.

Troubled, Aiden spends long nights with Adria, who consoles him as best she can. It is believed that Leah is conceived during one of those nights.

Aiden leaves Tristram in the night, heading east.

Adria leaves for Caldeum with Gillian and assures her that she will find a cure for her nightmares.

Demons attack Tristram and burn it to the ground. Nobody is spared but Cain, who is caged and has to witness the townspeople being reanimated in grisly undeath and Griswold being corrupted into a demonic beast.

Cinematics

Introduction (The Sister's Lament)​

Marius flees from the corruption of the Rogue Citadel high in the mountains past the Eastern Gate.

He end up in what look like an opium den where he tries to fight the nightmares off, already starting to go mad from the evil he witnessed in the Rogue Citadel.

The Dark Wanderer finds Marius, then seems to lose control, summoning many demons, burning the establishment and killing any witness in the process.

The Dark Wanderer beckons Marius. Marius feels he has to follow him. From that moment, they travel together east.

Act II (Desert Journey)​

They travel east, over the mountains and into the vast deserts.

The Dark Wanderer tells Marius that he had once been a great warrior, and that a dark and secret burden now weighs heavily upon him.

They travel across the desert for countless days, until they reach Lut Gholein.

That night Marius has a dream about the capture of Baal. The Horadrim had cornered Baal and attempted to imprison him within a Soulstone. When that failed, Tal Rasha volunteered to contain the demon within himself, completing the prison. He was bound within a tomb, buried under the sand, there to wrestle with the demon for all eternity.

The Dark Wanderer informs Marius that this is his brother.

The next morning they head toward the Tomb of Tal Rasha.

Act III (Mephisto's Jungle)​

Marius and the Dark Wanderer enter the Tomb of Tal Rasha. The Dark Wanderer seems to be gaining strength but is in reality losing what is left of his humanity.

The Dark Wanderer attempt to free Baal but is stopped by Tyrael, the two then begin to fight.

Baal tricks Marius into releasing him.

Tyrael chastises Marius for releasing Baal and commands him to go to Kurast where he will find the gate to the Burning Hells. He tells him to go trough that gate and take the Soulstone to the Hellforge, where it must be destroyed.

Powerless against the two Prime Evils, Tyrael is imprisoned in the tomb.

Act IV (Enter Hell)​

Marius finds the temple of the Zakarum and in the deepest recesses of the temple, he witnesses a dark gathering: the Wanderer; Tal Rasha; and the Lord of Hatred himself, Mephisto!

The Three perform a ritual to open an infernal gate to Pandemonium.

Diablo takes his true form then steps through the gate.

Marius is left maddened by what he saw and ends up in a sanitarium.

Epilogue (Terror's End)​

Marius is visited by a cloaked figure he believes to be Tyrael.

The hooded man tells him he has been searching for him for a long time.

Marius says he's sorry then tells the man his story, then he adds that he heard that the Soulstones were destroyed in the Hellforge, all expect one.

Marius then breaks into tears telling the man he's sorry that he couldn't do as he had asked.

The hooded man asks him for the Soulstone. Telling him all will be forgiven.

Marius gladly hands over the Soulstone pointing out what it did to him (aged him significantly over only a year).

The hooded man takes the Soulstone and reveals himself as Baal (still under the form of Tal Rasha), he then kills Marius and sets the asylum ablaze.

Lord of Destruction Intro (The Search for Baal)​

Baal (now in his true form) and his army stand at the gates of Sescheron.

After a short discussion with an emissary, Baal kills him and his army marches on the barbarian city.

Lord of Destruction Outro (Destruction's End)​

After performing some sort of ritual, the Archangel Tyrael throws his sword (El'Druin) at the Worldstone, shattering it.

Game

Act I​

The corrupted rogue Blood Raven, leader of a Rogue band that once fought Diablo at Tristram, is defeated in the Monastery graveyard.

Cain is rescued from his cage in Tristram and decides to join the heroes on their quest.

The demoness Andariel is defeated in the catacombs of the Rogue Monastery.

The heroes travel to Lut Gholein with Warriv's caravan.

Act II​

The Summoner, a Vizjerei who once fought Diablo at Tristram, is defeated in Horazon's Arcane Sanctuary.

The demon lord Duriel is defeated within the tomb of Tal Rasha.

Tyrael is freed from his imprisonment in the Tomb of Tal Rasha by the heroes.

The heroes travel to Kurast in Meshif's ship.

Act III​

The heroes catch up with the Dark Wanderer, but they are unable to stop him as he disappears in smoke, leaving behind demonic beasts.

Mephisto is defeated under the jungles of Kehjistan in a Zakarum temple.

Natalya travels to the Barbarian lands of the North.

After picking up Mephisto's Soulstone, the heroes step through the infernal gate to the Pandemonium Fortress.

Act IV​

The corrupted angel Izual is defeated and freed from his imprisonment in a hellish creature.

Diablo is defeated in his innermost sanctum.

The Soulstones of Mephisto and Diablo are destroyed at the Hellforge.

Act V​

The elders of Harrogath sacrifice themselves to erect a protective ward around the city, only Nihlathak survives.

Nihlathak strikes a deal with Baal. In exchange for Baal's mercy he gives him the Relic of the Ancients, an artifact that will allow Baal to enter Mount Arreat unchallenged by the Ancients.

Baal and his army march on Mount Arreat.

The heroes travel to Harrogath through the portal opened by Tyrael.

Baal fuses his Soulstone with the Worldstone so that he can corrupt it and in the process corrupt all of humanity.

The heroes best the Ancients and enter Mount Arreat.

Baal is defeated in the Worldstone Chamber.

The heroes take Tyrael's portal to escape to safety before Tyrael shatters the Worldstone.

Year 1264. Adria gives birth to Leah in Caldeum and leaves her in the care of Gillian.

Year 1265. As a result of the shattering of the Worldstone, Mount Arreat explodes ravaging much of the countryside and decimating Baal's army.

~Year 1265-1285. Cain tries to complete the Prophecy of the Ends Days.

Year 1272. Cain adopts Leah, she is 8 years old.

~Year 1280. Cain travels with Leah to research the Neztem Petroglyphs, found on a natural pillar far out in the desert of Aranoch. Upon staring at this rock, Leah began having visions of a most violent nature.

~Year 1280. Emperor Hakan dies and is succeeded by his son who is still a child.

In DII it is said that Mephisto, along with Baal, was originally captured in the desert near Lut Gholein. In the DIII timeline it says: Mephisto is captured near the jungles of Kehjistan.

In DII it is said that the Ancients are the spirits of the Nephalem, the Ancient Ones. But the Arreat Summit says that they were barbarians chosen by the Ancients.

The writings of Abd al-Hazir say that the Tristram Cathedral was built around 912 over the vault where Diablo was imprisoned, but Diablo hadn't even been exiled to Sanctuary at that time.

The DI manual says that after their exile the Three Brothers ravaged the lands of the Far East for countless centuries, but in the game it is stated that they did so for decades. In the current timeline 50 years pass between their exile and capture.

Before he came to Khanduras Leoric was originally a northern lord, this has been changed to an eastern lord.

In the Sin war trilogy the robes of the order of Dialon are azure, they should be crimson. While the robes of the order of Mephis should be azure instead of black. (to match the color of their Soulstone)

There are many errors in Scales of the Serpent, where the statue of Dialon has a hammer instead of tablets and where the one of Bala has tablets instead of a hammer.

In Scales of the Serpent the high priest of Dialon is named Arihan and is said to have had his title for a long time, but in Birthright all the high priests are named (Malic, Herodius and Balthazar) and Arihan isn't part of them.

Abd al-Hazir mention that Zoltun Kulle was a Vizjerei mage and as evidence cites the Demonicus de Zoltun Kulle. In the Book of Cain, Cain suspect Zoltun was a Ennead mage.

Well, one thing you've missed on your list of sources is, err, Diablo III Game [TBR]! Also official web sources - Arreat Summit had some beastiary bits that weren't in the manuals and some of the stuff in the current D3 gameguide and the Abd al-Hazir entries on the old D3 site probably won't be in the hardcopy manual.

The other potential sources are the D&D pen and paper sourcebooks [Awakening, Diablerie and To Hell And Back]. The problem with those is that they have lots of mistakes and places where deliberate changes were made to fit a different playstyle. Still they have some nice little details in - nothing with huge implications but it's kinda nice to have names for the wounded townsman and Asheara's python. I'd definitely put those in the "correct unless anything else contradicts them" pile.

I'd include Deckard Cain in the list of Horadrim [inferior as he is] and Aiden in Other Humans.

The Void and where Trag'Oul is/was probably count as other realms. Plus there's the hinted at other Trag'Oul-like beings watching over other worlds - which ties in so neatly with the Cornerstone Of The World lore in Hellfire that I wish it was cannon. But then other than that Hellfire is just a side story with no real implications, so you can kind of include it or ignore it as you wish and it makes no difference.

It is indeed a great idea, though sure to be frustrating at times. I'm doing some research into the Worldstone for an article of my own, and had no idea there were so many contradictions and unanswered questions on the subject. :scratchchin:

You might also want to add Adria and Leah to your list of "other" humans. I know we don't quite know what role they will play in D3 yet, but it's sure to be a major one.

Sure is, I'm trying to get more info on when exactly did Izual make his assault on the Hellforge (before or after the creation of Sanctuary) and details are scant.

EDIT2: also does anyone know what length of time "an age" represent. Like it this quote:
His maddened spirit has resided within that tortured husk for many ages now.

I'm tempted to think it's about the same as the duration of a lifetime but I can't find anything that would confirm it. And it's kind of weird that an immortal entity would use it, although since time is irrelevant to them i guess it makes sense that they would use such a vague term.

EDIT2: also does anyone know what length of time "an age" represent. Like it this quote:
His maddened spirit has resided within that tortured husk for many ages now.

I'm tempted to think it's about the same as the duration of a lifetime but I can't find anything that would confirm it. And it's kind of weird that an immortal entity would use it, although since time is irrelevant to them i guess it makes sense that they would use such a vague term.

Click to expand...

Well in geological terms an age is of the order of millions of years (but not tens of millions). When used in more general terms the timespan is highly variable - it can mean years, decades, centuries... and is defined more in terms of events than a specific timescale e.g. the golden age of cinema, the middle ages, the stone age. I'd take it in the context given to mean centuries at the very least but there's no way to narrow it down without further evidence.

Due to the lack of information I had to surmise the chronology of some events, hopefully the Book of Cain will add more information.
Let me know if you think that makes sense.

Inarius is turned over to Mephisto in return for Mephisto casting his mark on the point of flux inside the cathedral of light.
Izual attacks the Hellforge.
Izual is defeated, he turns over the secrets of the soulstones to the Prime Evils and help them plan their exile to Sanctuary.
Izual spirit is bound within a terrible creature summoned from the Black Abyss, left to wander the Burnings Hells for eternity.
First civil war in the Burnings Hells
Dark Exile
Second civil was in the Burnings Hells

Now for the speculation. Mephisto had a reason for wanting Inarius in his keep otherwise he would not have "casted his mark" (whatever that means). Perhaps from him he got the knowledge he needed to begin to corrupt an angel (Izual) who had the knowledge he desired (bypass whatever casting his mark did).

Izual, now partially corrupted goes against the wishes of Tyrael and attacks the Hellforge as a ploy so he can be captured by the Prime Evils without raising suspicions. The Prime Evils learn of the soulstones and how to corrupt them from Izual and begin to plan how to trick the Angels in using the soulstones against them.

So they stage their exile by perhaps even secretly instigating the civil war by letting the lesser evils think that they were afraid to continue the war with the High Heaven, instead focusing on Sanctuary. They are then exiled and roam Sanctuary leaving chaos and attrition in their wake, this to trick the angels into using the soulstones against them. They may even had a hand in the shattering and fragmenting of Baal's soulstone to force Tal Rasha to sacrifice himself in an attempt to contain Baal in a partial soulstone (This was a trick so that Baal could then take over Tal Rasha, in the same way that Diablo took over Aiden, and gain his knowledge and abilities).

Does anyone know where the idea that Andariel is the daughter of Lilith comes from?

In the Book of Cain it says:
Andariel is the twin sister of Duriel

and Lilith is not the mother of Duriel nor could she be, in fact the only descendant of her that I know of is Linarian aka Rathma.

EDIT: oh it's from The Arreat Summit. But since the pandemonium event isn't even cannon I guess we can ignore that.

Click to expand...

Yeah. I'm actually surprised that the Arreat Summit hasn't been updated with the new information we've got...but I guess they've got to leave it up in some form to account for the appearance of Lilith and the other bosses in the game.

There are other contradictions, too...for example, yesterday morning I realized that if the Pandemonium Fortress houses the Worldstone...what purpose had the Worldstone Keep served? I know it's gone now, but should we consider it to have been an extension of the Pandemonium Fortress on the mortal plane? Kind of like a mystical version of Doctor Who's TARDIS, with more blood and body parts. :scratchchin:

And props to Neinball for that Star Wars link, that's a very cool idea. Though we'd probably have to corner Chris Metzen and get him to clarify what's canon and what isn't.

There are other contradictions, too...for example, yesterday morning I realized that if the Pandemonium Fortress houses the Worldstone...what purpose had the Worldstone Keep served? I know it's gone now, but should we consider it to have been an extension of the Pandemonium Fortress on the mortal plane? Kind of like a mystical version of Doctor Who's TARDIS, with more blood and body parts.

Click to expand...

I think the Worldstone Keep was formed after the Sin War Trilogy as a result a the pact made between the High Heavens and the Burning Hells concerning the Worldstone. Probably to keep anyone else from altering it. (they probably couldn't move is back to the Pandemonium Fortress since that would have required the Angiris Council and the Prime Evils working together)

As a side-note, it seems Horazon lived for quite a while. in d2 Drognan says that nearly a thousand years ago he created for himself an Arcane Sanctuary.

An since he noted to tomb of Tal Rasha in his journal that mean he lived for at least 710 years!!!!

The lore panel at Blizzcon seemed to emphasise that the Worldstone was still in Pandemonium, it seems to exist in all worlds. By 'stealing' it Inarius et al really just hid it from everyone outside Sanctuary.

They also suggested that for that reason the worldstone may not really be destroyed. Or at least not permanently. Or something. The fact they brought that up at all suggests it was probably either a red herring or something they don't intend to explore in D3.

As for the Worldstone Keep, wasn't it there in The Sin War Trilogy? Didn't Uldyssian have to battle Bul'Kathos to gain entry? Or was it somewhere else?

And yes, I seem to remember somewhere (probably an NPC gossip) it saying (or at least suggesting) that the Arcane Sanctuary itself extended Hoarzon's life. Possibly time moves slower there - but I can't remember if it actually said that or if that's me filling in the blanks.

The lore panel at Blizzcon seemed to emphasise that the Worldstone was still in Pandemonium, it seems to exist in all worlds. By 'stealing' it Inarius et al really just hid it from everyone outside Sanctuary.

They also suggested that for that reason the worldstone may not really be destroyed. Or at least not permanently. Or something. The fact they brought that up at all suggests it was probably either a red herring or something they don't intend to explore in D3.

Click to expand...

There is a lot of misinformation and contradictions concerning the worldstone which makes it difficult to discern the truth.

For example at the end of the Sin War Trilogy it is hinted at that the Worldstone would be attuned to let the power of humans grow (or at least not suppress their power), but then again in the lore panel they said that the Worldstone did suppress their powers (among other things).

But yes they said that technically the Worldstone was still in Pandemonium, but somehow "dimensionally veiled it" and blinked it out in the realm of Sanctuary.

As for the Worldstone Keep, wasn't it there in The Sin War Trilogy? Didn't Uldyssian have to battle Bul'Kathos to gain entry? Or was it somewhere else?

Click to expand...

In the Sin War Trilogy it only referred as Mount Arreat, a place of Inarius's making. Although Bul-Kathos infers that there might be other guardians, there is not evidence of it in any of the books. Even then Bul-Kathos only seems to protect Mount Arreat from humans, as both Inarius and Lilith were able to access the worldstone without his knowledge. Unlike the Ancients who guard Mount Arreat from everyone (expect those possessing the relic of the ancients)

And yes, I seem to remember somewhere (probably an NPC gossip) it saying (or at least suggesting) that the Arcane Sanctuary itself extended Hoarzon's life. Possibly time moves slower there - but I can't remember if it actually said that or if that's me filling in the blanks.

Click to expand...

You are correct Drognan says:
"He believed that his Sanctuary would not only protect him from Hell's vengeance, but also allow him to continue his studies free from the ravages of time and disease."

Wow, there are so much contradictions in the Beta, I hope those thing are fixed before release.

It is hinted at that Lazarus was already possessed by Diablo before Leoric moved to Tristram, and that it is Lazarus who chose Tristram as Leoric new seat of power. Whereas Diablo awakened after Leoric moved to Tristram.

We have just arrived in Tristram, and I must say I'm a bit dismayed. This place is a backwater filled with serfs and an ancient broken down monastery, hardly fit for the king of Khanduras! I cannot fathom why Lazarus was so intent on this becoming our new seat of power.

Aiden was off to become a warrior before Leoric sent his armies against Westmarch, so he couldn't have been part of the war as was said in the lore panel.

A fetid, pallid malaise has fallen over the manor we now call home. Young Albrecht seems to be enjoying himself in our new home, however, even with his brother Aidan off to become a warrior. Perhaps I am simply suffering from an imbalance of humors brought on by the recent change of clime.

^ I'm not sure either of those are contradictions. The first doesn't seem to imply he's possessed to me; Lazarus was Leoric's top advisor, why shouldn't he exert some influence over such an important decision?

And "off to become a warrior" could simply mean he'd gone off to train, which presumably he'd finish in time to join the army of Khanduras for the war. The question of what took him so long to get back to Tristram remains, however. I'd be much happier if Aiden wasn't in the war, then we could assume he went off on his own path (as could also be interpeted from that lore entry) and didn't decide to return home for several years. It seems hard to believe that he'd not do anything about his father's madness or death unless he was well and truly out of contact. Maybe he went swanning off right after the war, without going home, but that feels very off to me. Is there anything besides the lore panel to say he did go to Westmarch?

In the Sin War Trilogy it only referred as Mount Arreat, a place of Inarius's making. Although Bul-Kathos infers that there might be other guardians, there is not evidence of it in any of the books. Even then Bul-Kathos only seems to protect Mount Arreat from humans, as both Inarius and Lilith were able to access the worldstone without his knowledge. Unlike the Ancients who guard Mount Arreat from everyone (expect those possessing the relic of the ancients)

Click to expand...

I always assumed, structurally, it was always as we see it in D2 and that the Ancients were recruited as B-K's replacements at some point. In any case, it's hardly surprising Inarius and Lilith would be able to gain access to the chamber, regardless of who was guarding it or how the defenses were structured - they created it after all. (Or at least Inarius did and Lilith was privy to all the details.)

I just re-read the Arreat Summit entries on the Ancients, and unfortunately there isn't anything that could help date their recruitment.

Well, we can perhaps infer an answer from the Overlords entry of the D1 manual beastiary:

Overlords (Tyrannus Pinguis)
Even the Seraphim are not immune to the corruption of the Dark Lords. One such angel, Inarius, was proud of his beauty and boasted loudly of his purity and worth. His thoughts became so clouded that he believed himself to be above both Angel and Demon, and he left the High Heavens to form his own dominion. He constructed a great cathedral of mirrored glass and crystal, and followers flocked to him, drawn by his numinous charm and wealth. Once Inarius had gathered a sizable army, he decided to prove his power.
Inarius first laid siege to an infernal temple devoted to the worship of Mephisto, but made the foolish mistake of overestimating his prowess. The armies of Inarius laid waste to the temple and killed the dark monks that dwelled within. The Three Evils had considered the vain warrior a mere nuisance and amusement until this time, but this was an insult that they could not bear.
Mephisto himself is said to have appeared at the cathedral of Inarius. He laid waste to the church and the surrounding countryside. The Lord of Hatred took the proud archangel and his followers captive. He bound Inarius with tremendous chains and slowly tore the wings from the back of the angel. Great barbed hooks were then used to stretch out the once glowing skin and his features were distorted by vile powers. Many of the followers of Inarius were given as gifts to Baal and Diablo, but the rest were molded to match the bloated image of the now crippled angel. To this day, Inarius is said to be trapped in Hell within a chamber of mirrors, his eyelids torn from his face as he is forced to gaze upon his misshapen form for all eternity. His misguided followers now serve as Hell’s taskmasters, taking the anguish of their lost glory out upon the bodies of others.
These grotesque demons have considerable brawn hidden beneath their layers of greasy flab. Do not underestimate their strength or their intelligence for crossing swords with them is ill advised. You will be far better served to combat them with ranged weapons or magic.

We know, thanks to Abd Al-Hazir, that early Vizjerei writings (specifically including this particular book) aren't especially reliable, so perhaps it's not too surprising that some important details - like that Inarius' domain was in fact Sanctuary, or exactly how Inarius fell into Mephisto's possession - might be misrepresented. The descriptions of the specific tortures also seem unlikely given what we now know of angel physiology. All that said, in the absense of any other information I think we can take from that that Inarius remains Mephisto's prisoner, undergoing eternal torture based upon his own vanity. I tend to doubt the actual Overlord connection though (there was no suggestion of Mephisto getting his hands on any of Inarius' followers in the novels was there?).